General Science Previous Year Questions (PYQ) with Answers – Page 83

A unisexual flower carries only one kind of reproductive organ, either stamens or a pistil, while a bisexual flower carries both.

Power is the work done divided by the time taken, and here the work is the potential energy the boy gains while climbing the staircase.

Green plants use sunlight trapped by chlorophyll to join carbon dioxide and water, and the balanced equation reads six molecules of carbon dioxide plus twelve of water giving one molecule of glucose, six of oxygen and six of water.

The grooves cut into a sole grip the ground, so the foot does not slip while walking or running. Friction is the force that acts between two surfaces in contact and opposes motion between them.

The pulmonary artery is the one artery in the body that carries deoxygenated blood. It leaves the right ventricle and takes blood that has returned from the body's tissues to the lungs, where carbon dioxide is given up and fresh oxygen is picked up.

Pressure counted from a perfect vacuum as the zero point is called absolute pressure. A perfect vacuum holds no gas and exerts no pressure, so it is the true zero of any pressure scale.

The hepatitis B vaccine was the first vaccine made by recombinant DNA technology.

In human beings the sperm meets and fuses with the egg inside the fallopian tube, also called the oviduct. The ovary releases one egg in a month, and the funnel shaped mouth of the fallopian tube collects it.

Hydra, starfish and planaria can all grow a lost or cut off part of the body back into a whole animal, and that ability is called regeneration.

Hydra is the one animal in the list that reproduces both by budding and by regeneration. In budding, a bulge grows out from the body wall of the parent Hydra, develops a mouth and tentacles, and then breaks off as a small independent Hydra.

Collenchyma cells lay down extra cellulose and pectin at the corners of their walls, which makes the tissue strong and yet flexible.

Papaya is raised from seed, so it is not multiplied by vegetative propagation the way the other three plants are.

Green plants give out oxygen only during photosynthesis, the process in which they use light energy to make their own food.

Hexane, C6H14, can be drawn as a straight chain of six carbons, as two chains of five carbons with a methyl branch in different positions, and as two chains of four carbons carrying branches, which gives five different structures with the same molecular formula.

Calamine is zinc carbonate, and since it is a carbonate ore it is converted to the oxide by calcination, that is by heating in the absence of air, before being reduced to the metal.

Inertia is the tendency of a body to stay at rest or keep moving in a straight line, and the measure of that tendency is mass.

Johann Wolfgang Dobereiner, a German chemist, grouped elements of similar properties in sets of three that he called triads. His rule was that the atomic mass of the middle element is about the average of the other two.

Spirogyra is a green filamentous alga found in ponds, and when its filament grows long it simply breaks into two or more pieces.

A tissue is a group of cells that come from the same source, look alike and work together at one job.

Carbon occurs in nature in two ways, free and combined. In the free state the element stands alone, as in diamond, graphite and coal; diamond is pure carbon whose atoms are each joined to four others in a rigid three dimensional network, which is why it is the hardest natural…